Multiuser scheduling on downlink communications by using adaptive hierarchical modulation

In this paper, we propose a novel downlink system that is able to maximize the number of users which could be served with high correct decoding probability while, minimizing the total consumed energy for data reconstruction by whole users simultaneously. We deploy 2/4/…/2^N-ASK hierarchical modulation that enables multi-resolution transmission along with an energy harvesting system to implement a wise and efficient downlink system. In our scheme, there is one information sender and two decode-and-forward access-points each of them equipped with one transmission antenna that wish to successfully transmit data to the users based on their link quality. In order to minimize the total consumed energy by the users, we prepare energy access-point which is an harvester with the capability of harvesting energy from radio frequency radiations. Each time the transmission commences, our scheme based on the weighted difference relay selection method selects the best access-point that mutually is able to maximize the number of serving users via a smart users number-defining algorithm and minimize the total consumed energy of the users. We investigate the performance of such a system in terms of average error probability and provide upper and lower bounds on them. We also discuss about careful hierarchical parameter selection that maximizes the number of serving users.